Oils from lots of different oleaginous (oily) microorganisms are being looked at as possible biodiesel feedstock alternatives to plant-based, and especially food-crop-based oil sources like soybeans. Microalgae are the most well-known of these organisms, but the list also includes yeasts, bacteria and fungi like the above mentioned m. cicinelloides.
As with many alternative biodiesel feedstocks, scalability is an issue at the moment, but the team in Spain believes that could be overcome by genetic manipulation of the fungus to produce higher lipid content (which means more oil in the fungus). Direct transesterification is already providing greater yields than expected, which could help make biodiesel from m.circinelloides profitable down the road.
[Source: Green Car Congress | Image: Skidrd - C.C. License 2.0]